Apparatus for briefly and impulsively releasing mechanical energy

ABSTRACT

A piston (3) for impulsively delivering mechanical energy is connected with a crank shaft (5) having a pin (5a) in co-action with a first coupling member (2a, 2b) on a rotatable member (2). The pin (5a) forms a second coupling member, which accompanies the movement of the rotatable member (2) during one half revolution thereof, whereupon an energy-absorbing means, for example, a spring (4) arranged around the piston (3) is compressed. When the rotatable member (2) has reached a limit position, the coupling engagement between the coupling members is instanteously broken, whereupon the energy stored in the spring or the like is transferred to the piston, which executes an impulsive percussion movement. The cycle is repeated when the coupling member (2a, 2b) of the rotatable member is again brought into engagement with the pin (5a).

This is a continuation of application Ser. No. 688,448, filed Jan. 8,1985 abandoned.

TECHNICAL FIELD

The present invention relates to an apparatus for briefly storing andimpulsively releasing mechanical energy. Such apparatus can findapplication and use in many fields within the technique, for example inconnection with various percussion tools and apparatus, punches andpresses, rock-drilling machines, compressors and high-pressure pumps,and the like.

More specifically, the invention can be said to relate to an apparatusfor stepping-up the mechanical power output of machines. In thisrespect, energy is stored by means of an arrangement having acomparatively low power output over a relatively long period of time,and is thereafter released impulsively over a very short period of timeat a high power output, whereby it can be said that the power input hasbeen stepped-up.

More particularly, according to one aspect of the invention there isprovided an apparatus for briefly storing and impulsively releasingmechanical energy with the use of a stepwise or continuously rotatingmember arranged to coact with a power-delivering device, e.g. a piston,which when moving in one direction causes energy to be stored in anenergy-absorbing means, e.g. a spring, gas or liquid, which energy,subsequent to said member passing a limit position, is delivered to saiddevice, so as to produce an accelerated movement in the oppositedirection.

BACKGROUND ART

Various apparatuses of this kind are known to the art. Reference can bemade in this respect, by way of example, to various types of known camand link-drive mechanisms, such as those of the kind described inArtobolevsky: MMED, Volume IV, No.: 3011, 3014, 3015 and 3016. Theseprinciple cam and link mechanisms can be used to produce normallycomplicated movement sequences, which also include the release ofpercussion forces at given times in the movement sequence.

U.S. Pat. No. 740,816 (Daily) describes an apparatus comprising acircular rotatable disk formed with a cut-away portion designed as asemiheartshaped cam. Along said cam moves a small roller which iscoupled to a spring adapted to store energy. Compression of the springcommences at the point at the biggest distance from the disk's centerand is released--however not instantaneously--at a point nearest thecenter.

Other types of apparatuses having outer cams are described in U.S. Pat.Nos. 870,653 (Warsop) and 1,137,272 (Moyle).

None of these known mechanisms, however, can be used successfully in amachine of the aforesaid kind, since among other things the wear onmutually co-acting components subjected to load would quickly render themechanism unusable. Neither are these mechanisms capable of effectivelystepping-up the power output of a machine, and hence are not competitivein relation to other types of mechanisms available on the market.

Also known to the art is a high-speed cutting or shearing machine whichuses a compressible spring in co-action with a release coupling whichcomprises a number of balls housed in a sleeve and arranged to lock ahammer in a retracted position. The hammer is released by lifting thesleeve, so that the balls are able to move out of locking engagement.

When the movements of such high-speed cutting or shearing machines areto be coordinated with the feed of the workpieces to be worked,production is restricted thereby to a maximum of 350 strokes per minute.Present day demands, however, require a marked increase in the workingrate of such machines, and in the case of an eccentric press for examplerequire a working speed which is at least twice that of theaforementioned, e.g. a working speed of 750-1000 strokes per minute, orstill higher.

OBJECT OF THE INVENTION

One object of the invention is to provide an arrangement of theaforementioned kind which, despite the simplicity of design and therobust construction of said arrangement, provides a much faster workingrate than known mechanisms.

Another object of the invention is to guide the power-delivering deviceeffectively with a minimum of frictional losses when utilizing anarrangement of the aforesaid kind.

BRIEF DISCLOSURE OF THE INVENTION

These and other objects are fulfilled according to the invention bybringing a first coupling member, e.g. a recess defined by a projection,on the rotatable member into engagement with a second coupling member,e.g. a pin, connected with the power-delivering device and dogging thesecond coupling member through part of a revolution during rotation ofsaid rotatable member, and causing the engagement of said couplingmembers to be broken under the action of stored energy as the aforesaidlimit position is passed, so as to impart to the power-delivering devicean impulsive movement in the opposite direction.

Because of the simplicity of the design of the coupling means, e.g. acoupling which simply comprises a recess defined by a projection andco-acting with a pin which is in connection with the power-deliveringdevice, there is obtained an effective connection between the twocoupling parts, without any marked time-lag or frictional losses. Theremaining apparatus components can be of simple and robustconstructional design intended to promote the efficiency of the methodaccording to the invention, thereby to provide a higher production ratethan that achieved with methods known hitherto.

In practice, during the aforementioned movement of the power-deliveringdevice, the second coupling member is preferably arranged to move freelyrelative to a closed curve located radially inwardly of the periphery ofthe rotatable member, and to be captured by said closed curve, a part ofsaid curve forming the first coupling member.

Because the rotatable member is provided with a closed curve inwardly ofits periphery, the second coupling member is guided accurately andreliably in a path having constant radius during that part of itsmovement in which it is in contact with said curve. When thepower-delivering device executes its impulsive movement under theinfluence of the energy stored in the energy-absorbing means, the secondcoupling member will move freely relative to the curve, to beimmediately brought back possibly into contact with said curve, althoughwith no risk of skewing or damage of any form to the curve or couplingmeans.

When practising the invention, the coupling members will remain inmutual engagement through approximately one-half revolution of therotatable member. The second coupling member thereby moves and acts likean excentric shaft.

During the remaining half revolution of the rotatable member, the secondcoupling member moves in the aforesaid manner, i.e. freely andimpulsively to a diametrically opposite location possibly but notnecessarily on the curve, at which location said second coupling memberremains more or less stationary until it is again brought intoengagement with the first coupling member, for a further working cycle.

It will be understood, however, that said one half of the curve can begiven differing forms, to cause the power-delivering device to move inthe manner desired. Consequently, the appropriate part of the internalcurved camming surface of the rotatable member can be shaped accordingto requirements.

It is also preferred in practice that movement of the second couplingmember in the coupled position is transmitted to the power-deliveringdevice through a crank arrangement. In this case, the second couplingmember, which as beforementioned may have the form of a simple pin orpeg, will function as a "floating shaft".

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a perspective view of a principally simple hand-operatedapparatus according to the invention, intended to illustrate theprinciple of the invention.

FIG. 1b is a cut-away view in larger scale of the rotatable member ofthe apparatus, showing the associated first coupling member in aposition in which it has just been brought into engagement with thesecond coupling member.

FIG. 2a is a perspective view of the arrangement illustrated in FIG. 1a,illustrating the position where the engagement between the couplingmembers is about to be broken.

FIG. 2b is a perspective view in larger scale of the rotatable memberand the coupling members in said position.

FIG. 3 is a side view of the rotatable member, and shows the first andsecond coupling means in the position where the second coupling meanshas left the first coupling means and executed a downwards impulsivemovement.

FIG. 4 is a side view corresponding to the view of FIG. 3, showing theposition in which the first coupling member is about to engage thesecond coupling member.

FIG. 4 is a partially cut-away front view of essential components of amodified apparatus incorporating double rotatable members and couplingmembers in symmetrical arrangement, for use in a shearing or punchingmachine for example.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to FIGS. 1a-4, an apparatus 1 according to the inventioncomprises, in its simplest form, a frame 10 which has mounted thereon astraight-guide 11 and plates 12, 13 and 14 for guiding apower-delivering device of a hole punch, for example the piston 3 of theillustrated embodiment. The piston co-acts with a spring 4 arrangedthereon, said spring being compressed during upward movement of thepiston, to store mechanical energy thereby. The upper end of the pistonis connected to a crank shaft 5 by means of a pivot pin 5b while theupper end of the crank shaft carries a coupling means in the form of apin or peg 5a arranged in a cylindrical roller 6. The roller 6 forms aguide in a rotatable member 2 journalled in the frame 10, said rotatablemember being arranged for stepwise or continuous rotation by means of adrive means, such as the illustrated crank handle 7, for example.

As will be seen from FIG. 1b, the rotatable member 2 has an inner cavitywhich accommodates the roller 6, and that radially inwardly of theperiphery of the rotatable member there is arranged a curve comprisingthree sections 2a, 2b and 2c.

The inwardly projecting curve section 2a and the adjacent recess-formingcurve section 2b, partially defined by said projecting curve section 2a,forms a first coupling member associated with the rotatable member 2,which first coupling member--as illustrated in FIGS. 2b, 3 and 4--can bebrought into engagement with the pin 5a, which thus serves as a secondcoupling member.

The first coupling member 2a, 2b of the rotatable member 2 is broughtfrom the position illustrated in FIG. 1b into engagement with the pin,i.e. the second coupling member 5a, to cause said second coupling memberto accompany the first coupling member 2a, 2b in its rotation to theposition illustrated in FIG. 2b, in which position the spring 4 has beencompressed to its maximum while storing mechanical energy therein.

The spring 4 therewith exerts a downwardly acting tension force on thesecond coupling member 5a, and when the first coupling member 2a, 2b hasreached the position illustrated in FIG. 3, the first coupling member isno longer able to hold the second coupling member, whereupon the secondcoupling member is moved impulsively downwards with an acceleratedmovement, whereupon the energy stored in the spring 4 can be utilized,via the piston 3, to carry out mechanical work or to produce a poweroutput.

The second coupling member 5a is captured on the opposite part of thecurve 2a, 2b, 2c, and immediately after reaching the positionillustrated in FIG. 4, the first coupling member 2a, 2b will soon againengage the second coupling member 5a, i.e. the coupling positionillustrated in FIG. 1b is re-newed so as to carry out a further workingcycle.

The coupling member 5a can be said to constitute a "floating shaft", theposition of which during one half revolution of the rotatable member 2is determined by the first coupling member 2a, 2b. It then moves like aneccentric shaft in a path having constant radius. However, it thenleaves the first coupling member and moves freely to the positionillustrated in FIG. 3 in which it may but preferably does not touchcurve 2c. In practice, the rotatable member may comprise two parts,namely a coupling housing 2d and a cover 2e which is connected to thecoupling housing 2d and which incorporates the curve 2a, 2b and 2c.

Subsequent to the piston 3 having executed a working stroke, it ispossible that the energy-absorbing means, i.e. the spring 4 in theillustrated embodiment, will still contain energy. Preferably, thisresidual energy is taken-up by a damping means, so as not to be releasedbetween the second coupling member, i.e. the pin 5a and the surface 2cof the curve, i.e. in a no-load condition the pin should be in contactwith the surface of curve section 2c.

Consequently, the illustrated embodiment is provided to this end with adamping means in the form of a resilient ring 13b, which encircles thepiston 3 and which is made, for example, of urethane, said ring restingon the lower guide plate 13. In turn, the guide plate is adjustablyarranged on the frame 10 and is provided for the said purpose withlateral guides 13a and an attachment means 13c which enable adjustmentof the plate 13 and therewith also adjustment of the damping effect ofthe damping means.

The upper plate 12, which forms an abutment for the energy-absorbingmeans, is provided with corresponding lateral guides 12a and can also beadjusted relative the frame 10, by means of a fixing means 12c. First,by adjusting the vertical position of the plate 12 it is possible toaffect the amount of energy stored in the energy-absorbing means, i.e.the spring 4.

In the FIG. 5 embodiment, like components are identified by likereferences. This figure illustrates the upper part of the apparatus, andillustrates a double arrangement of symmetric design.

The arrangement is intended for continuously rotating the rotatablemembers 2, said rotating being effected through a drive shaft 7 via twogears 7' which engage two gears 2' which are concentrically connectedwith the rotatable members 2. The rotatable members are oppositelyarranged and are, in principle, of the same design as that illustratedin FIGS. 1-4.

In the FIG. 5 embodiment the shaft 5 also comprises a crank shaft, whichcarries a journal pin 5a which extends upwardly in both directions andserves as said second coupling member. Arranged on either end of thejournal pin 5a is a respective guide roller 6. The arrangement isincorporated in a frame 10.

As will be understood from the aforegoing, the energy-absorbing meansmay have many different forms. For example, in addition to acompressible spring 4 of the kind illustrated in FIGS. 1-4, a gas orliquid may be used, said gas or liquid being suitably located in acylinder and acted upon by a plunger co-acting with the power-deliveringdevice 3 and the shaft 5.

It has also been mentioned in the aforegoing that the curve section 2cin the rotatable member 2 may also have a varying form in order toimpart to the power-delivering device 3 varying movements after itsimpulsive movement. In certain cases it may be expedient, for example,to return the device 3 rapidly subsequent to carrying out a workingstroke. This can readily be achieved by corresponding design of thecurve section 2c.

Industrial Application

As beforementioned, an apparatus according to the invention can be usedfor many different purposes, such as percussion or power-generatingmeans for punching, shearing, pressing operations etc., although theinvention can also be applied to various types of high-pressure pumpsand compressors, and for other percussion purposes, such as withrock-drills for example. There are also numerous other conceivablefields of application.

I claim:
 1. A high speed punch press apparatus for briefly storing andimpulsively delivering mechanical energy, comprising:(a) a circularrotatable member (2), (b) means (7) for rotatably driving the rotatablemember, (c) a relatively light weight, linearly reciprocable powerdelivering device (3), (d) an elastically compressible energy absorbingmember (4) operatively coupled to the power delivering device forcompressively storing energy during movement of the power deliveringdevice in one direction and for expansively releasing such stored energyto rapidly move said device in an opposite direction at a rate ofacceleration substantially exceeding that of gravity upon the rotatablemember passing a limit position, such that the resulting impulsiveenergy delivery rate exceeds 750 strokes per minute, (e) a firstcoupling member (2) defined by the rotatable member, and (f) a secondcoupling member (5a) connected to the power delivering device by a crank(5) and operatively disposed for engagement with the first couplingmember, wherein:(1) the first coupling member comprises a closed curvewithin the circular rotatable member successively defining, in adirection of rotation thereof, a single, inwardly extending, tooth-likedogging projection (2a), a single adjacent, outwardly extending recess(2b) radially spaced from a center of the rotatable member, and acircular arc (2c) having a constant radius substantially equal to aradius at a greatest depth of the recess, wherein said closed curve thusapproximates the shape of a central vertical section through an apple,and (2) the second coupling member comprises a follower pin configuredto mate with and nestingly engage within the recess and the doggingprojection for movement in a constant radius path from a lower releasedposition to an upper, diametrically opposite position whereat therotatable member is at its limit position such that the follower pinmovement repetitively approximates that of a semi-circular path inengagement with the recess closed by a diametrical path free of anyengagement with the first coupling member.
 2. An apparatus according toclaim 1, wherein the rotatable member includes a housing (2d) which isconnected to a drive shaft and which accommodates a roller (6)connecting with and surrounding the second coupling member (5a) to forma guide therefor.
 3. An apparatus according to claim 2, wherein thehousing is provided with a cover (2e) which defines the first couplingmember (2a, 2b) and the closed, apple shaped curve (2c).
 4. An apparatusaccording to claims 1 or 3, wherein two rotatable members (2) aresymmetrically arranged and adapted to co-act with a respective secondcoupling member (5a) on a common shaft arranged to co-act with a crankshaft located between the rotatable members (2b), and the rotatablemembers are arranged to co-act with gears (2'), each of which engages arespective gear (7') on a common drive shaft.